Psoriasis is a kind of a chronic skin disorder most often positioned on the scalp, elbows, knees, and lower back of the patient, which presents silvery scales covering affected parts. The patient severely suffers from it. As a result, psoriasis significantly impacts patients' daily-life and work.
Recently a great number of patients have been suffering from psoriasis. However, psoriasis is very difficult to cure, and has been considered by the WHO one of the most important diseases to treat and prevent in the dermatological field.
The pathogeny of psoriasis has not been very clear. It is generally considered related with complicated factors such as heredity, infection, immunity, metabolizability, incretion, inflammation and psychological aspects.
Currently, it is the main way to treat psoriasis with medicaments though a lot of methods have been used. However, it is too difficult to avoid relapsing. By now cortical hormones or immunosuppressants have been used for the treatment (see: Progress of External Cortical Hormone Medicaments, Yaoxuetongbao, 1985, 20(9). Although the cortical hormone can reach a good short-term effect, it will make the epidermis and dermis of the affected part thinner, causes side effects such as induce telangiectasis and addiction of the medicaments and induces other complications, if used for a long time. Meanwhile, these medicaments cost expensive.
Chinese medicine cnidium fruit (also called “fructus cnidii” or “common cnidium fruit”), used for the treatment of diseases was recorded in ancient medical books. Cnidium fruit has been used in clinic for treating surgical, gynecological, dermatological and otolaryngological diseases such as lichen, scabies and scrotum eczema, because the Chinese believed that cnidium fruit has effect of “wetness-removing”, “worms-killing” and “itch-stopping”. However, there have been no reports on the treatment for psoriasis with total coumarins of an extract of cnidium fruit.